• Journal of the Korea Society of Computer and Information
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• v.9 no.2
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• pp.57-62
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• 2004

In these days, application systems for processing information using database is increasing. Enterprises holding a lot of data do not possess needed data but instead include unrelated, independent and individual data. As a result, it only contains disparate data. Disparate data is ambiguous and it does not support current integrated information. In response to the above problems, data warehouse may provide a solution. Building a data warehouse needs a systematic design because of its complexity. This paper describes an efficient design methodology using visual environment for data warehouse to cope with the requirements of end users. Also, the system is able to process existential SQL query.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.569-572
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• 2004

최근 데이터베이스를 이용한 정보처리응용 시스템이 증가하고 있는 추세이다. 이러한 응용 시스템의 데이터를 종합적으로 분석 처리하여 사용자 요구에 신속하게 응답할 수 있도록 다양하고 고품질의 정보 서비스를 지원하기 위해 데이터 웨어하우스 환경에 관한 연구가 많이 이루어지고 있다. 이러한 환경을 제공하기 위해서는 많은 데이터 정보가 요구되며, 이를 분석하여 사용자 의사 결정에 적합한 정보 추출 수행은 기존의 관계형 데이터베이스 환경의 테이블들에 대한 질의 수행에서 시간적인 낭비 요소가 많이 존재한다. 그러므로 본 논문에서는 사용자 질의에서 자주 요구되는 사실 혹은 데이터를 통합, 저장 및 수행하기 위한 테이블 생성을 사용자가 직접 선택 정의함으로써 편리하게 테이블 생성할 수 있도록 설계 및 구현한다. 또한 본 내용에서 포함되는 내용으로 기존 일반적인 SQL 질의를 수행할 수 있도록 한다.

• Journal of KIISE:Software and Applications
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• v.37 no.7
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• pp.503-517
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• 2010

Service-oriented computing, the effective paradigm for developing service applications by using reusable services, becomes popular. In service-oriented computing, service consumer has no responsibility for managing services, just invokes services what service providers are producing. On the other hand, service providers should manage any resources and data for service consumers can use the service anytime and anywhere. However, it is hard service providers manage the quality of the services because an unspecified number of service consumers. Therefore, service scalability for providing services with higher quality of services specified in a service level agreement becomes a potential problem in service-oriented computing. There have been many researches for scalability in network, database, and distributed computing area. But a research about a definition of service scalability and metrics of measuring service scalability is still not mature in service engineering area. In this paper, we construct a service network which connects multiple service nodes, and integrate all the resources to manage it. And we also present a service scalability framework for managing service scalability by using a mechanism of service migration or replication. In section 3, we, firstly, present the structure of the scalability management framework and basic functionalities. In section 4, we propose scalability enhancement mechanism which is needed to release functionality of the framework. In section 5, we design and implement the framework by using proposed mechanism. In section 6, we demonstrate the result of our case study which dynamically manages services in multi-nodes environment by applying our framework. Through the case study, we show the applicability of our scalability management framework and mechanism.

• Journal of the Korea Convergence Society
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• v.13 no.1
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• pp.31-42
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• 2022

The purpose of this study is to analyze the reference data of the National R&D Report database built by the Korea Institute of Science and Technology Information(KISTI) to derive problems and to find complementary points for the construction technical items in the system. To this end, we investigated the descriptions of references in the National R&D Report constructed in the KISTI DB and analyzed the construction process, guidelines, types, items, etc. Based on this, the appropriateness and accuracy of the classification results of the reference types constructed with the DB were checked. As a result, the problems of the items built into the system and corrections to the construction guidelines were derived. Through this, database construction can proceed efficiently and data quality is expected to improve. In addition, a follow-up study was proposed on the convergence service plan that can be provided in the future through standardization of technical regulations.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.3
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• pp.233-250
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• 2012

The purpose of this study is to assess the development, current states, and problems of MEDLIS document delivery service. With the analysis of MEDLIS transaction data from 2001 to 2011, we identified continuous usage decrease, unbalanced contribution by type of institution, high dependence on back issues, use differences among subfields of medicine, relatively low success rate, and various reasons for failure. Based on the results, recommendations for the maintenance of union catalog database, technical support for search capability enhancements, establishment of back issue archiving policy, user training and publicity, and membership expansion are suggested to promote the service.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.473-480
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• 2019

The smart home is a technology that can monitor and control by connecting everything to a communication network in various fields such as home appliances, energy consumers, and security devices. The Smart home is developing not only automatic control but also learning situation and user's taste and providing the result accordingly. This paper proposes a model that can provide a comfortable indoor environment control service for the user's characteristics by detecting the user's behavior as well as the automatic remote control service. The whole system consists of ESP 8266 with sensor and Wi-Fi, Firebase as a real-time database, and a smartphone application. This model is divided into functions such as learning mode when the home appliance is operated, learning control through learning results, and automatic ventilation using indoor and outdoor sensor values. The study used moving averages for temperature and humidity in the control of home appliances such as air conditioners, humidifiers and air purifiers. This system can provide higher quality service by analyzing and predicting user's characteristics through various machine learning and deep learning.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.123-135
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• 2011

The domestic market of database in Korea is estimated to be over 3.663 trillion won. The data migration is getting to be more important along with the continuous growth of the database industry. g-CRM and private recommending function are examples of the service that can be given through coupling among customer database, product database, geographic information database, and others. The core infrastructure is also the database which is integrated, perfect, and reliable. There are not enough researches on efficient way of data migration and integrating process and investigation of migrated data though trends of database in IT environment as above. In connection with this issue, we have made a model for data migration on scientific and technological contents and suggest the result of data migration process adapting that model. In addition, we verified migration's exhaustiveness, migration's consistency, and migration's coherence for investigation of migrated data and database. From the result, we conclude data migration based on proper model has a significant influence on the database consistency and the data values correctness and is essential to maintain high qualified database.

• Journal of KIISE
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• v.44 no.8
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• pp.767-773
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• 2017

In a distributed system environment, such as a cloud database, the tail latency needs to be kept short to ensure uniform quality of service. In this paper, through experiments on a Cassandra database, we show that long tail latency is caused by a lack of memory space because the database cannot receive any request until free space is reclaimed by writing the buffered data to the storage device. We observed that, since the performance of the storage device determines the amount of time required for writing the buffered data, the performance degradation of Solid State Drive (SSD) due to garbage collection results in a longer tail latency. We propose a garbage collection synchronization technique, called SyncGC, that simultaneously performs garbage collection in the java virtual machine and in the garbage collection in SSD concurrently, thus hiding garbage collection overheads in the SSD. Our evaluations on real SSDs show that SyncGC reduces the tail latency of $99.9^{th}$ and, $99.9^{th}-percentile$ by 31% and 36%, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.459-461
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• 2010

Ad-Hoc VoIP system is an important IP phone technique used in MANET networks. In small-scale networks, VoIP system could be built easily while keeping the Qos on a acceptable level. Although Ad-Hoc VoIP system is designed as 'Client-Server' model, due to the property of MANETs that no Base Stations working as servers, we have the SIP Server with promary funtions worked on mobile terminals instead. In this paper, we explored how to build VoIP systems in MANETs and achieved the construction from within linux.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.69-75
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• 2016

The performance of a web application is an essential issue to provide high quality of the services in interactive web environments. On a sudden increase in traffic in a very short span of time, the servers became CPU starved and would become unresponsive. This would lead to a bad experience for the clients of web service. This paper deals with the effects of two configurable software settings of J2EE application servers: the maximum size of the thread pool and the maximum size of database connection pool. In order to figure out the optimum configuration value, this paper builds experimental evaluation method for web performance analysis. Finally, a case study related with the proper experimental method is presented with performance result.